摘要:

Sodium butyrate (butyrate), 5‐azacytidine (5Aza‐C), dimethyl sulfoxide (DMSO), and dimethyl formamide (DMF) were applied to a human melanoma cell line for the purpose of inducing pigmentation and terminal differentiation. The results are summarized as follows: 1) butyrate, DMSO, and DMF had a strong cytostatic effect, arresting cells in the G1phase of the cycle; 2) butyrate caused a morphological change to spindle shape whereas DMSO and DMF produced rounded cells, without affecting the levels of vimentin and intermediate filaments; 3) tyrosinase activity and melanization were stimulated by DMSO and DMF but not by butyrate; 4) butyrate induced several membrane‐bound enzyme activities (alkaline phosphatase and ‐γ‐glutamyl transpeptidase); 5) changes in the expression of antigens related to tyrosinase activity (2B7 and 5C12) only partly corresponded to the changes in enzyme activity; 6) expression of the melanosomal B863 antigen was decreased by butyrate, DMSO, and DMF; and 7) the action of DMF resembled that of DMSO whereas 5Aza‐C had little effect. The results indicate that these differentiating agents activate different sets of genes, the melanogenic pathway being activated independently of ‐γ‐glutamyltranspeptidase. The down regulation of B8G3 antigen by these agents may provide a common focus for understanding the essential action of differentiation inducers

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1990.tb00294.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

We compared tyrosinase activity (TH, DO, and native PAGE‐defined isozymes) and melanin production in participate and soluble fractions of hairbulb melanocytes of lethal yellow (Ay/aC/C), nonagouti black (a/aC/C), and albino (a/a c2J/c2J) of 3‐, 6‐, 9‐, and 12‐day regenerating hairbulbs. With respect to tyrosine hydroxylase (TH) and dopa oxidase (DO) activities,Ay/amelanocytes possessed only 25‐35% of the activity ofa/a; there were no genotype differences in either the subcellular distribution of activity in soluble and particulate fractions or in the relative increases of activity over the 12‐day developmental period. TH data on wild‐type agouti (AwJ/AwJ) mice over the 3‐11 day regeneration interval showed an activity intermediate between that ofa/aandAy/a; the rate of TH increase reflected black and yellow phases of the agouti hair cycle. Analyses of the number and densities of dopa‐sensitive bands following native PAGE of 3‐, 6‐, 9‐, and 12‐day hairbulb fractions ofa/aandAy/amice suggested stage‐dependent patterns. A comparison of rates and amounts of melanin production in 3‐, 6‐, 9‐, and 12‐day fractions showed consistent melanin production inAy/ato be 10‐20% that ofa/a; however, fold increases in melanin production over the four stages were similar between genotypes. Overall, tyrosinase activity data support the notion that agouti locus modification of tyrosinase activity is a graded or quantitati

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1990.tb00295.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

That the ventral integument of adult frogs (Rana pipiens) contains factor(s) that stimulate iridophore expression (adhesion, morphologic appearance, proliferation) was demonstrated on iridophores derived from tadpoles ofR. pipiensandPachymedusa dacnicolor, and maintained in primary culture in a growth medium based upon Leibovitz's L‐15. Experimental growth medium (VCM) conditioned by a one‐hour exposure to pieces of ventral skin of adultR. pipiensinduced iridophores to assume a broad and stellate appearance, to form confluent sheets, and to proliferate over a nine‐day period. Iridophores in control medium assumed long thin profiles, detached easily, and exhibited no signs of proliferation. Unknown cells containing reflecting platelets and unusual other organelles appeared uniquely in chromatophore cultures ofP. dacnicolorin VCM. The intense stimulation of iridophore expression in VCM is consistent with the known inhibitory effect of this medium on melanization and with its purported role in the determination of dorsal/ventral pigment patterns of amphibians. The results are discussed in terms of a prevailing theory about pigment cell origins and develo

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1990.tb00296.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1990.tb00297.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1990.tb00298.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY